By classical definition, the term "dry cleaning" has been used to describe processes for cleaning textiles using nonaqueous solvents. Dry cleaning is an old art, with solvent cleaning first being recorded in the United Kingdom in the 1860's. Typically, dry cleaning processes are used with garments such as woolens which are subject to shrinkage in aqueous laundering baths, or which are judged to be too valuable or too delicate to subject to aqueous laundering processes. Various hydrocarbon and halocarbon solvents have traditionally been used in dry cleaning processes due to their ability to dissolve and remove oily soils and stains. However, the need to handle and reclaim such solvents has mainly restricted the practice of conventional dry cleaning to commercial establishments.
While solvent-based dry cleaning processes are reasonably effective for removing oily stains from fabrics, they are not optimal for removing particulates such as clay soils, and may require special treatment conditions to remove proteinaceous stains. Traditionally, particulates and proteinaceous stains are removed from fabrics using detersive ingredients and operating conditions which are more akin to aqueous laundering processes than to conventional dry cleaning.
In addition to the cleaning function, dry cleaning also provides important "refreshment" benefits. For example, dry cleaning removes undesirable odors and extraneous matter such as hair and lint from garments, which are then generally folded or pressed to remove wrinkles and restore their original shape. Of course, such refreshment benefits are also afforded by aqueous laundering processes.
As can be seen from the foregoing, and aside from the effects on certain fabrics such as woolens, there are no special, inherent advantages for solvent-based immersion dry cleaning over aqueous cleaning processes with respect to fabric cleaning or refreshment. Moreover, on a per-garment basis, commercial dry cleaning is much more expensive than aqueous cleaning processes.
There has been a continuing search for new, safe and environmentally acceptable solvents for use in dry cleaning. Unfortunately, many such solvents are expensive and, as noted, require a recycling apparatus to provide for their recovery and re-use. In any event, such solvents function merely as a result of their ability to dissolve oily stains, and are thus somewhat limited in their cleaning power.
The present invention employs a novel approach to the dry cleaning operation. Succinctly stated, in the present process enzymes are used to degrade soils and stains, thereby enhancing their removal. For example, while conventional dry cleaning uses only solvents, or solvent/surfactant mixtures, to dissolve or emulsify, and only incompletely remove, stains such as the lipids present in foods, the use of lipase enzymes according to the present invention fragments the lipids into smaller, more soluble molecules, thereby enhancing their likelihood of removal.
Accordingly, it is an object of the present invention to provide dry cleaning compositions and processes which employ enzymes such as lipases, proteases, amylases and mixtures thereof, to degrade lipids, proteinaceous soils and saccharidic soils, respectively. It is another object herein to provide dry cleaning compositions and processes which are suitable for in-home use. It is another object herein to provide non-immersion dry cleaning compositions and processes. These and other objects are secured herein, as will be seen from the following disclosure.